(Photo : Photo by John Moore/Getty Images)
As seen from the air, a copper mine hole in the Sonoran Desert near Casa Grande, Arizona.

The Casa Grande Ruins National Monument in Coolidge, Arizona announced on Wednesday that it would be closing its picnic area through April 30 due to a proliferation of stinknet, a sickening weed native to South Africa that some say has an odor similar to turpentine. 

"Stinknet can cause severe skin rashes and serious breathing problems. For the safety of visitors and their health, we ask that you do not enter the picnic area," park officials said.

"We also ask that visitors avoid walking near or stepping on this flowering weed in other areas of the park to avoid spreading it."

The offending plant can grow up to two feet tall and features round yellow blossoms that are golf ball-shaped in appearance. Park officials said they are working on a solution to reopen the picnic area "as soon as possible."

The monument is an attempt to preserve ancient canal irrigation systems and farming structures built by the ancestral Sonoran Desert people from which the Hopi, O'Odham, and Zuni peoples descend. 

The Casa Grande, or Great House, is one of the largest prehistoric structures ever built in North America, and, according to the park, "its purpose remains a mystery." 

The invasive plant which has already taken root in Phoenix was first found and collected in the state in 1997, according to the University of Arizona.

The plant then spread south along the Interstate 10 corridor and into Pinal County, which is where the national monument is.

— with reporting by TMX